Traveling power take-off shafts, appropriate to the state of the technology, have been installed in agricultural vehicles, for example in tractors, which have live axle connections, saddle supported distributors of fertilizer, drilling machines, and the like. In such cases, the traveling power take-off changes its rotation speed along with the traveling speed of the tractor, so that the speed of rotation of the take-off-shaft and the speed of the tractor remain continually in the same ratio, one to the other.
In normal practice, power take-off shafts of this kind are clutch connected at the speed of rotation of the motor directly by means of predetermined gear stage ratios. For some applications in agricultural work, it becomes necessary to have, independent of the transmission ratio, a desired rotational speed ratio between the wheel and take-off power shaft, this being particularly true in cases of driving a trucking vehicle.
According to the state of the technology, traveling power take-off shafts were connected to the output shaft by direct mechanical clutch. This practice resulted in excessive mechanical complexity. In this case—independent of the speed of rotation of the motor—a definite ratio was established between the speed of rotation of the wheels and the speed of rotation of the power take-off shaft.
EP 0 511 480 B1 discloses a changeable transmission for the drive of a power take-off shaft as applied to a farm tractor, wherein an input shaft with at least two driving gears, an output shaft with at least two free gears and an interposed, shiftable, sleeve clutch whereby the free gears are in continual mesh with the driving gears but free in respect to the input shaft. Between the driving gears is placed, in addition, a lamella clutch, which can be hydraulically activated. Moreover, at least one driving gear, located on each side of the said lamella clutch is rigidly bound to its housing.
EP 0 967 107 B1 of the applicant, teaches a method for the control of a drive unit having a stepless, adjustable transmission. Upon the installation of this drive unit into a tractor with a power take-off drive, a gas pedal is provided to serve as a power lever and also present is a manual gas lever. During a period of active manual gas operation, the position of the said manual gas lever determines a control value for the drive motor. The position of the gas pedal demands a shift of the transmission ratio, so that, by means of the gas pedal the travel speed is fixed and by means of the manual gas lever, both the travel speed and the power take-off shaft rotational speed are controlled.
The purpose of the present invention is to make a method available for the operation of a traveling power take-off shaft in clutch connection with a drive motor, which enables an interaction of the wheel and power take-off shaft by electronic means so that different ratios between the rotational speeds of the wheel and the traveling power take-off shaft can be obtained.